Frequently Asked Questions

Compostable plastic can degrade into its end state, which includes carbon dioxide, water, and biomass, under conditions of time, temperature, and humidity. Biodegradable plastic concludes with extremely micro components of the monomer or polymer, which will last as long as on the planet with the possibility of migrating to numerous living organisms. The natural end-of-life process does not work for any biodegradable plastic.

Compostable plastic does not produce any microplastics since natural microbes can break down the fundamental elements contained within the compostable plastic under the given environment for degradation. For polylactic acid (PLA), lactic acid is the construction element or monomer unit. When PLA is subjected to hydrolysis (degradation), it will begin to form lactic acid, which is a natural microbial food in the soil.

Aerobic degradation takes place in industrial composting facilities, under required oxygen levels, temperatures usually between 55°C and 60°C, and at least a humidity level of about 50%. This process involves biological breakdown in compostable plastics, where the long polymer chains are initially broken down into smaller molecules like oligomers and monomers through enzymatic activity and hydrolysis. These degraded molecules are then broken down by microorganisms within the composting environment to eventually form biomass, carbon dioxide, and water. Through this process, compostable plastics become incorporated into natural cycles without any residues left in the soil.

Compostable plastic can endure its properties for a period of up to 12 months under indoor storage conditions. With conditions outdoors such as higher humidity and sunlight it can have a shelf life of 6 months. Depending on formulations, these properties can be retained.

In India, compostability certification follows the ISO 17088 standard, which sets out the criteria for plastics that are to be composted. In order to meet the requirements of this standard, products have to go through severe testing in a government-approved controlled composting facility to determine their biodegradation, disintegration, and eco-toxic effects. The Central Institute of Petrochemicals Engineering and Technology (CIPET) grants the certification and carries out the necessary tests and grants approval for compostable plastics. Additionally, manufacturers are required to label certified products clearly as “Compostable” and include the registration details to ensure traceability and regulatory compliance within the Indian market.

Compostable plastic products fall under Extended Producer Responsibility (EPR) compliance and are classified under Category IV. According to the Plastic Waste Management Rules, 2024 (and amendments), producers, importers, and brand owners of compostable plastics must carry out certification from the Central Pollution Control Board (CPCB) for proof of compostability according to ISO 17088 standards. They also have to meet commitments toward collection, processing, and end-of-life treatment of these products to avoid contribution to plastic pollution.

The end-of-life process for compostable plastics typically involves treatment in an industrial composting facility, where the material is converted into biomass, carbon dioxide, and water under carefully controlled conditions. Factors such as moisture, humidity, and temperature are precisely managed to ensure effective degradation within the facility.

Compostable plastics can biodegrade fully within a 6-month time period under a certified industrial composting plant. It could take about 2-3 years for the total biodegradation by keeping in view regular landfill soil.

Compostable plastic items can be fully dissolved in the DCM solvent, whereas non-biodegradable plastic cannot. Thermoplastic starch-based compostable material will only dissolve in the DMSO solvent. Compostable plastics contain polar chemical functionality that is able to interact favorably within the polar DCM solvent that leads to solvation of the polymer chain.

Traditional plastics such as Polyethylene (PE), Polypropylene (PP), Polyvinyl chloride (PVC), etc., consist of robust molecular bonds that cannot be degraded by microorganisms even in composting conditions. Compostable plastics such as PLA, PHA, Thermoplastic starch, and PBAT are designed chemically to degrade under industrial composting conditions.

Oxo-degradable material has traditional plastic such as PE or PP as a base polymer with certain chemical components which can assist in initiating the degradation into smaller pieces under exposed conditions such as water, UV, humidity, and temperature. The end fragmented non-degradable plastic content of PE or PP will remain in the landfill in its original form as microplastics.

Compostable plastics cannot be reused or mechanically recycled because of the biodegradation process. Chemical recycling of compostable plastics will be the future in order to sustain the renewable resource and decrease the cost.

The inorganic filler, such as calcium carbonate, does not exhibit any naturally occurring hydrolysis chemical design since it is not naturally biodegradable. In addition, Calcium carbonate-filled biodegradable plastics are not appropriate for the end-of-life choice to produce good-quality soil or fertiliser. The constant deposition of calcium carbonate can alter the soil PH and shift the natural biodegradation process.